This invention relates to a self-energizing synchronizer for a transmission.
Self-energizing pin-type synchronizers are known for use in step ratio transmissions to reduce shift effort and/or shift time. One such synchronizer, as shown in U.S. Pat. No. 5,901,824 to R Nellums and incorporated herein by reference, includes a radially disposed shift flange supported for limited rotation and non-axial movement on and relative to an annular member. The annular member is mounted in a shaft for non-rotation and axial movement relative thereto and includes jaw clutches that engage jaw clutches affixed to ratio gears. The self-energizing means includes a radially movable link that reacts between cams affixed to the flange and the shaft.
The synchronizer disclosed herein improves several features of the above synchronizer. The improvements include simplifying synchronizer assembly, eliminates flange to annular member retainers that need to be installed during assembly, improves rigidity of components associated with the self-energizing means, reduces unit stresses acting between the annular member and link, and improves jaw clutch contact for reducing jaw stress under high torque load.
An object of this invention is to provide a self-energizing synchronizer with improved structure and assembly.
Another object of this invention is to provide a self-energizing synchronizer with improved self-energizing means.
According to a feature of the invention, a self-energizing synchronizer for frictionally and positively connects first and second drives disposed for relative rotation about a common axis; the synchronizer comprising: an annular member including a first jaw clutch non-rotatable relative to the first drive and axially movable relative to the drives from a neutral position to an engaged position with a second jaw clutch for positive connecting the drives in response to engaging movement of the first jaw clutch by an axially directed shift force (Fo) moving a radially extending flange toward the second jaw clutch. The flange has axially oppositely facing sides and a radially inner portion receiving an annular outwardly facing surface of the annular member. Retainer means connects the flange for axial movement with the first jaw clutch. A first friction member is axially movable into engagement with a second friction member in response to an initial portion of the engaging movement of the first jaw clutch for producing an initial synchronizing torque. First and second blocker surfaces are movable into engagement in response to the initial synchronizing torque for preventing asynchronous engagement of the jaw clutches, for transmitting the shift force (Fo) to effect an engagement force of the friction members, and for producing a torque counter to the synchronizing torque for moving the blocker surfaces out of engagement as synchronization is reached. The first blocker surfaces are defined by a plurality of circumferentially spaced apart pins rigidly extending axially from the first friction member and into openings in the flange. The second blocker surfaces are defined about the openings and the pins are operative to transmit the synchronizing torque to the flange. Self-energizing means include a plurality of circumferentially spaced first cam means affixed to the flange, an equal plurality of circumferentially spaced apart second cam means affixed to the first drive, an equal plurality of circumferentially spaced apart and radially extending openings in the annular member, and a radially movable link deposed in each opening. Each link has radially outer and inner ends respectively disposed for engagement with the first and second cam means and operative when engaged to react the synchronizing torque therebetween for producing an additive axial force in the direction of the shift force for increasing the engagement force of the friction members.
The improvement is characterized by the retainer means including axially spaced apart first and second abutments extending radially outward from opposite axial ends of the annular member outwardly facing surface for axially embracing the flange sides. The first abutment includes a plurality of circumferentially spaced about tabs circumferentially offset from the openings and receiving slots in the radially inner portion of the flange for allowing positioning of the flange sides between the abutments during assembly of the synchronizer.
According to another feature of the invention, a synchronizer for frictionally and positively connecting first and second drives disposed for relative rotation about a common axis; the synchronizer comprising: an annular member including a first jaw clutch non-rotatable relative to the first drive and axially movable relative to the drives from a neutral position to an engaged position with a second jaw clutch for positive connecting the drives in response to engaging movement of the first jaw clutch by an axially directed shift force (Fo) moving a radially extending flange toward the second jaw clutch. The flange has axially oppositely facing sides and a radially inner portion receiving an annular outwardly facing surface of the annular member. Retainer means connects the flange for axial movement with the first jaw clutch. A first friction member is axially movable into engagement with a second friction member in response to an initial portion of the engaging movement of the first jaw clutch producing an initial synchronizing torque. First and second blocker surfaces are movable into engagement in response to the initial synchronizing torque for preventing asynchronous engagement of the jaw clutches, for transmitting the shift force (Fo) to effect an engagement force of the friction members, and for producing a torque counter to the synchronizing torque for moving the blocker surfaces out of engagement as synchronization is reached. The first blocker surfaces are defined by a plurality of circumferentially spaced apart pins rigidly extending axially from the first friction member and into openings in the flange. The second blocker surfaces are defined about the openings and the pins are operative to transmit the synchronizing torque to the flange. Self-energizing means include a plurality of circumferentially spaced first cam means affixed to the flange, an equal plurality of circumferentially spaced apart second cam means affixed to the first drive, an equal plurality of circumferentially spaced apart and radially extending openings in the annular member, and a radially movable link deposed in each opening. Each link has radially outer and inner ends respectively disposed for engagement with the first and second cam means and operative when engaged to react the synchronizing torque therebetween for producing an additive axial force in the direction of the shift force for increasing the engagement force of the friction members.
The improvement is characterized by each first cam means including a first pair of cam surfaces facing radially inward and axially spaced apart, and each link has axially spaced apart first and second flange portions joined together in H-shaped fashion by a web portion with surfaces of the flanges and web in close sliding relation with mating surfaces of the opening. Radially outer portions of the first and second flanges define a first pair of ramp surfaces engagable with the first pair of cam surfaces, and a radially inner portion of the web defines a second ramp surface engagable with the second cam means.